Apparatus for distillating tar



Aug. 16, 1932. sd. P. MILLER APPARATUS FOR DIISTILLATING TAR Filedv June 3.. 1927 4 Sheets-Sheet 1A uw Nw WAQWINTSOO ATTORNEY5 ug., 36, 1932. s. P. MILLER J 1,871,550

v APPARATUS FOR DISTILLATING TAR Filed June 5. 1927 4 She'ets-Shee'r,` 2

Aung. i, 3932. s. P. MILLER APPARATUS FOR DISTILLATING TAR n Filed June 3. 192'? 4 sheets-sheet 4 INVENTOR ATTORNEYS Patented Aug. I6, 1932 -tioninvolvesl the provision of heat b the' combustion of some'suitable fuel an' the s'rUAErrAauELEE immun, or mENAELY, NEw JE'EsEY, AssreNoB 'ro 'mE BARRETT conm. 0E NEwyoE'L-N. Y., n coEPoEArIoN or NEW 'arraanrusron DrsTILLa'rING 'ran "Apucaama1a':une s, 1927. serial Nu. incase. .I

Thisjnvention relates to improvements in the distillation of tar, and particularly to the utilization fof the heat 'available in the.

gases produced in'lcoal-ca'rbonization lants to dist-ill tar and to produce clean o' 'and pitches by such distillation. The invention' will bedescribed Aespecially with reference to its application to coke ovens.

Tar derived from 'various sources "such as coke ovens, gas-house retort's, vertical retorts Vand Water-gassets, is shipped ordinarily"y from the plant where'itis produced toa tardistillation, plant to be`heated in stills for for the purpose'of driving oi the more volatile constituents: of the tar; Such distilla- -consequent cost of the fuel as well as the expense of providing and "maintaining 'the necessar distillation equipment.

It 1s the object of' the present invention to provide for the .distillation iof tar at a coalavailable'in coal-distillation gases by spray-1 l the gases produced by` the'batteryfto distillthe tar and oils btainedjtlerefrom. 'The ,.retort's, etc. Provision maybe made, therefore, in accordance with the present invention" to utilize any. desiredquantity of; the -hot tar and aoi s as hereinbefore. described. In large installations Vtheflieat from ailfentire battery can b e used to distill tar from other batteries. Usually', however', it is sullicient 5 to utilize the from a.. selected number the tarinthe distillation operations. The

carbonization plant by utilizing the heatl ingor otherwise bringing thetarinto intimatecontact with such gases while the latter are at high temperatures. The invention may be applied, for example, to byproduct coke ovens which afford a source o large volumes of foul -gases which escape from the ovens at vtemperatures .of vfrom 600 to 700 C. ,or

higher.

The heat-available suchgases by a coke-ovenbatt'ery is many times the amount required to .distill allof the tar and oils recovered from the battery, Consequentit is necessary to utilizeonly aportmn of heat can utilized, likewise, to distill `tar and oils from other sources such as gas-house coke-oven ases for the purpose of distilling and oils thusv recovered may of the ovens, the the remaining l ovens, being subjected in the usual manner to cooling'n the collector main and in condensers provided for the purpose of separating tar and oils from the ases. The tar utilizing the heat in the gases from the remaining'ovens of the battery toA produce pitches of the desired character'and clean distillatesj According to the present invention the hot -gases from the selected ovens are subjected,

preferably assoon as they are dischar ed, to intimate contact with tar or oil supp ed thereto Ain a finely divided form for the purpose of reducing the temperature of the gases and of distilling the tar or oil. The gases are then utilized -for the further distillation of the ytar and oil in a tank still,.fcr exam le,

in which the tar or oil to be distille isV ,mingled intimately with the gases. The tar orioil andthe pitch reduced therefrom in the separate distillation operations may be -be controlled likewise by varying the character of the material supplied as, for example, by introducing regulated amounts of oil with the tar. to be distilled or by supplying A'an aqueous cooling agent such as ammonia liquor either with the tar or oil or separately to the distillation apparatus. Regulation by 'the additionof ammonia liquor is particu-v larly effective by reason of the greater's eciiic those oftar and oil'.

is the cleaning ofthe gases after utilization thereof `by electrical' preci itatio'n., The gases which have been ming ed intimately with the tar or oil to be distilled carry therefrom not only the vapors resulting from the uantities distillation but 'also considerable of tar in the vform of globules or tar fog. They carry in addition solid particles of coal, coke, etc., which may not have been removed completely bythe scrubbing action distilled byv and latent heats of water as compare with rou solid and liquid particles and the tar fog indicated such as by the addition of oils or can be removed effectively gases through an electrical by passing the aqueous cooling agents either in the'stills or recipitator of in the connections leading thereto. `the type, for example, of t e well known From the tank still the gases, which are Cottrell precipitator. The ases leaving the considerably enriched in condensable constitprecipitator are free from so id particles and iuents b the successive distillations and carry tarry materials, and upon cooling yield clean.. also so id particles and tar in the form of oils which can be utilized for various com-f globules and tar fog, are directed prefermercial purposes, particularly if the cooling lably into an electrlcal precipitator. The is effected in stages to separate the oil con-is"v cleaning of the gases by the electrical precipistituents in fractions.

In carryingout .the invention the initialj distillation is effected preferably in `stills which are connected directly to the several uptake pipes of the selected ovens. Such A stills may com rise vertically disposed casings through w ich the gases pass upwardlyin intimate contact with the tar or oil whic is delivered in the form of a ine spray bytator consists in passin the ases to be treated between electrodes w ose ilerence in elec- ,trical potential is very great. I t is best to' 'spray nozzles to which the tar or oil is sup-- p 1 ed under a suitable ressure from a source thereof.' In passing t rou h the hot gases the tar or oil is distilledan the vapors join the ases and are carried away therewith, the pitc or residue collecting in the bottom of each still and flowing to the larger still for. further distillation by the gases.

The gases thuspartiaIl cooled and carrying the vapors resulting rom the initial dis-y tillation are delivered referably to a tank still which is disposed c osel adjacent to the uptake stills and connected t ereto so that the ases from the several ovens are combined.

n the latter still these gases are again intimately mingled with tar or oil to be distilled, the tar or oil being delivered preferably in the form of aline spray by spray nozzles provided for that purpose. The gases are thus further cooled and the heat thereof is utilized for the distillation of the tar or oil, the gases being thereby further enriched in `oil vapors while the residue fromy the tar or oil accumulates in the still. Portions of the pitch or residue ma be withdrawn and recirculated and again lntroduced in the form of spray so as to mingle intimately with the hot gases for further vdistillation and therecovery of more of the volatile constituents therefrom. a

The gases from the 'several uptake stills may be delivered thus through separate inlets to the still in which the heat of the gases is utilized or these gases can be combined and introduced thus to the still. The pitch produced in the individual 'uptake stillsruns into the larger tank still in which it is subjected to further distillation, either with or without admixture with additional tar or pitch introduced into such tank still; and the pitch can be recirculated to the uptake stlls for further distillation therein.V The cooling of the gases inthe' uptake stills avoids the separation of hard pitch and carbon in the connecting pipes and this result can be avoided also by suitable regulation of the temperature as hereinbefore use a rectified alternating current. The alternating current (the primary) lis sent through a step-up transformer to produce a high potential current (the secondary) which is then rectified to an intermittent uni-directional current, for example, by means of a rotary converter. The rectified current is delivered from the converter to the electrical precipitator at which it leaves t e transformer.

The electrical precipitator consists essentially of a, grou of vertical pipes with an 'axially located e ectrode in each which is supplied with the uni-directional hi h tension current, the ipes being connectedg to proper headers fort eintroduction and dischar eof the gases.' The pipes generally constitute the positive electrodes, and the axially located wires or rods the negative electrodes. The size of the pipes may vary, but in general pipes of less than six inches in diameter are. not used. Electrical precipitators with pipes six from,35,000 to 50,000 volts are satisfactory ractically the potential at i for the purpose of this invention. It is gen- 'I erally best to operate with maximum potential difference (secondary current) between the electrodes, this maximum being just below the break-down voltage at which arcing occurs.

The eiliciency of the cleaning is dependentupon several variables. Satisfactory cleaning of the gas may be accomplished if the time of treatment is of the order of one second, although this time may be varied widely dependingupbn the extent to which it is desired to prevent contamination f of the distilled products by tarry matter initially present in the hot gases. In working with six-- inch tubes, for example, nine feet in length, it is possible to substantially free the gases from all solid andliquidconstituents with a time of treatment ofkfrom one and one-half to two seconds, that is to say, with a gas velocity of from six feet to 4.5 feet per second. Thisv 'gives an eiliciency of cleaningof approximateloo `inches in diameter using secondary voltages l posed preferably closely adjacent tothe tank v still 'so that the gases reach the precipitator. still at relatively high temperature. The dew points ofthe gases :for the several vapor- Vized condensable constituents are lower than the boiling points of thesel constituents and by suitable regulation of the temperatures ofdistillation and of the subsequent cleaning of the ases in the electrical precipitator, it is possile to retain in the gases substantially all of the desired oil constituents in the vapor phase while the tarry constituents are present in the liquid phase and can bev separated, therefore, from the gases in the electrical precipitator. The temperature of operation of the electrical precipitator should, therefore, be above the dew point of the most readily condensable oil constituent desired and below that at which the tarry constituents are condensed. With such operation the maximum quantity of the desired oiliconstituents can be recovered and these constituents will be free from contaminating tarry material, If some of the oil constituents are to be retained in the tar or pitch recovered, the temperature at which the electrical precipitator is operated Will be modified accordingly so that this temperature is above the dew' points of' the gases for the constituents to be retained therein.

The gases and vapors leaving the electrical precipitator can be subjected to cooling for the purpose of condensing the volatile constituents therefrom. The cooling may be conducted so as to condense all or'nearly all of the volatile constituents in a single operation, or it may be progressive so that the va pors are condensed in fractions, thus producing oils having distinct boiling ranges and other characteristics which are essential :for the commercial application of such products. After such separation of the desired condensable constituents the gases may, if desired, be delivered to and mingled with the gases from the remaining ovens of the battery, for example, after the latter have been subjected to the usual primary treatment for the removal of tarry oils therein contained.

, The invention as herinbefore described embodies a single tank still with uptake stills connected to deliver hot coke-oven gases and partially distilled tar or oil thereto. 'It is possible, however, to use a plurality of tank stills with connected uptake stills and to circulate the tar to be distilled throu h such stills in series and to likewise convey t ie gases through the stills in various ways for the pur ose vof producing desirable pitch products an of enriching the gases in the vapori-zahle constituents of the tar. The tar to be distilled may be circulated through the tank stills and uptake stills in seriesor tar may be directed through the tank stills in series and other tar may be supplied to the uptake stills. The piflfehgproducts produced in the several stills may be'witlidrawn or they may be combined with other tar and redistilled in anotherstill of the series. The gases may likewise be passed in succession `through the tank stills either in the same direction 'or preferably counter-current .to the ow of tar or pitch therethrough. Various such arrangements can be employed for the purpose of modify ing the nature of the products. The temperature of the gasesl inthe uptake stills is higher than the temperature in the tank stills and consequently the amount of distillation in theuptake stills per unit volume of gases is or precipitators and then'through condensers to recover the condensable constituents. The tar to be distilled may be delivered first to the initial tank still and passed thence through `the uptake stills connected ltherewith. The pitch produced in the uptake stills may be delivered then to the second tank still and conveyed thence through the uptake stills connected therewith. The pitch may be conducted then through .the third tank still and thence through the uptake stills connected therewith from which it is withdrawn as a finished product. A portion of the pitch may be withdrawn from the tank stills and from the uptake stills so that pitches having various melting points and other characteristics can be recovered simultaneously from the s stem. The gases employed for distillation will carry oil vapors distilled from thev tar and pitch and after separation of terry constituents and solid particles in the electrical precipitators and the gases will upon cooling yield clean oils.`

The application of the invention requires no substantial change or modification of the usual coke-oven recovery system except for the .addition of the equipment required for distillation. Thus, the lovens of the battery may be connected through theusual uptake pipes to a collector main in which the gases may be cooled by sprays of ammonia liquor cooling medium or subjected to treatment for the recovery of 'ammonia therefrom. The gases, after separation of the tar and greater than in the tank stills and harder 1 or ammonia liquor and tar. The gasesm'ay isa oils, may delivered by the usual exhauster to the equipmentf'p'rovided for the separation of light oils andammoniaetc. The tar V"and oils may be subjected 'then to distillation eitheralone orl with theP addition of tars `fromother sources in. accordance with the invention. fThe distillation equipment is vis disposed.' conveniently at the rear of the ovens yand is connected to the .selected ovens of the battery .through separate uptake pipes "provided for that purpose. Valves Vmay be diepsosed in the uptake -pipes at the opposite en of the ovens to .permit direction of the gases eithersinto the collector lmain or into the distillation vapparatus as may be desired.

Thus, ythe coke-'oven-battery may be operated inthe usualmanner'j'when no tar is to be distilled. When distillation is desired the gases from the selected ovens .will'be diverted into the-distillation apparatus while the gases from 'the remaining ovens are-,subject- -ed in the normall manner to cooling for the purpose of separatingtar and oils` there- .rom..,l... The .present invention is of more or less fsgeneral application. to the; distillation of tarA and oils and the recove therefrom. The invention involves the utilization of the-hot gases from coal-carbonization plants for the, distillation of tar and -oil for the purpose of producing pitches' and clean oils therefrom. a.

The invention will be further illustrated by the following more detailed description taken with the', accompanying drawings which showa paratus `ein yin the inventionj and a apted for the practice there of, but it intended 'and will be understood thatthe invention'- is not limited to vthe spe- Ain the drawings, lin w ich Fig. 1 is a plan view of a portion of a 'y eek-eme Plantillustrang 'the application of the invention thereto; r

Fig. -2"isV an enlarged view,- partiallyin section, illustrating' the stills and the electrical precipitator;

Fig. 3 is a detail cal precipitator; v

Fig. 4 is a plan view of aportion of the .coke-oven--plant,illustrating a slightly difl y ferent arrangement of the apparatus;

Fig. 5 is. an enlarged .sectional viewqof the uptake "stills'connected" to la. collector main vfrom which the gases are delivered to the vsecond.still;.a nd`Vv Fig. 6 .illustrates diagrammatically an arl' il 4rangement of uptake stills and tank-stills battery of lcoke ovens in which ,the.individ'.

in connection with'fa coke-oven battery to permit continuous counter-currentdistilla-` tion vof tar and pitch. e

. Referring to the drawings, 5 indicates a ual ovens are connected by uptake pipesl and ggosemecks 6 toa collector'main7 having .dnsing which accumulate ,in the 'centre box` can be 4storage tank 16. VThe fof desired residues' .to the usual ci'ficl details ofthe ap stratus' as illustrated` in section the. electri-v a centre box 8 from which a crossover mill I 9 conveysthe gases' and vapors to the'consystem. .Y The tar` or lotheirf'liqiiids .withdrawn through a pipe 10. The tar 'which se arates in thecross-over main 9 is deliverby ay pipe 11 to adecanter 12 in which it 1s separated from ammonia liquor. The tar can be delivered through a pipe 13 to a storage tank 14 andthe ammonia liquor can be discharged through apipe 15 to, a pam through condenseis` 17 in' which they vare. further cooled'to separate oils. The latter are delivered throu h a pipe 18. to a decanter'19. The vvsepara oils through pipes 20 and 13 to the storage `tank 14er to separate a vtanli16 through a um 28 'and pipe 29 to spray nozzles .30 an 31 in the-collector main ,and the goose necks leading thereto for the purpose of cooling the gases as hereinbefore described.v `The structure as indicated is typical of a `by-product recover vsystem' em- -ployed in connection with co e-ovens. It

may be modified in. accordance with the' customary'or any desired practice.

, To facilitate the practice ofthe invention selected yovens of the battery may be provided with uptake pipes 32 which, as indicated in Fig. 2, are connected directly to uptake stills 33, the latter comprising casings into which the tar to be distilled is introduced through spraynozzles 34 which are supplied by pipes 35 from any suitable source, of tar or oil to be dist-ined.' The ar or oil which'is introduced i in the form of a fine spray passes downwardly in contact with the upwardly moving streams of hot coke-oven gases and is subjected there- -by todistillation toseparate the. more readily va'porizable constituents.- The pitch pro duccd can be delivered through 'a lpipe 35 toa still 36 to which a number of uptake 'stills are connected by pipes l37 having valves 38' therein to permit control of the operation.

The tar or oilto -be distilled in the uptake stills may be .withdrawn through a pump ,39, for example, from the still 36 anddeliv-I l ered -to the pipes 35 for recirculation through the uptake stills. v

be distilled may be supplied The tar or oil to fromfthe tanks 14 or 14 by a pump 40 and delivered througha pipe 41 to a plurality of iin spray nozzles 42 within'the The tar or oil is atomize'd by the spray nozzles and is The gases, after passing thoughthe still'Vv k36, escape through an'outlet 48 to an electrical precipitator 'comprising 'a vcasing 49 having` a plurality of tubes therein supported in heads 51 so that the gases, after passing a baiiie 52, are conveyed through the tubesto an outlet-53.` A pluralityof electrodes 54 are supported from a bus-ban at the top of the casing 49, and extend through the tubes. The bus-bar Y55 passes into casings 56 at the sides of the precipitator and is supported upon insulators 57 therein. Current is supplied through a conductor 58 from any suitable source of uni-directional high ten'- sion current. The electrodes 54 are normally negative and the casing 49 with the tubes therein is grounded and connected to'the positive side of the circuit. The arrangement of conductors and of the circuits whereby current is supplied to the precipitator forms no Ipart of the present invention.

n 4passing through the tubes of the precipitator the gases carrying entrained tar in the form of globules or tar fog, together with solid material such as carbon in finely divided form. are subjected to the electrical discharge which causes the suspended particles to separate from the gases. The separated liquid, together with the solid particles, run down the inner walls of the tubes into the chamber at the bottom of the precipitator and may be withdrawn through a pipe 59 and delivered to any suitable storage receptacle.

The gases which escape from the precipitator through the outlet 58 are delivered to n 4 b mingled with the hot gases delivered thereto throughv the 'goose-necks 93 and' alsqwifvde- :sired from the succeeding tank stills'91 and v92. The partially distilled tar is withdrawn a plurality of condensers 60 arranged in ries. In these condensers the gases are cooled in stages to effect the condensation of desired fractions of the oils. These fractions are delivered through pipes 61 to storage receptacles 62. The gases may be delivered then` byan exhauster 63 through a pipe -64 to the exhauster 27 and mingled there with the n gases from the remaining ovens of the battery.

The pitch which leaves the still 36 through the pipe 43 may be accumulated in a tank 65, and similarly pitch which is withdrawn from the electrical precipitator can be accumulated in the tank 66, although ordinarily this pitch will be returned as made to the still 36.

' Referring to Figs. 4 and 5 of the drawings,

vision of a short collector'main 67 to which the uptake` pipes 68 and stills 69 are connected. 'The gases which have been partially 4cooled by intimate'contact with'tar or oilin the' stills 69 aredelivered to the short collector 'main 67 and may be further cooled therein if desired bythe application of sprays of the tar or oilv or of aniaqueous cooling agent such as ammonia liquor. The are" delivered through a pipe 70 to a still 71 which maybe substantially identical with fthe still'36 previouslyfdescribed. Pitchlaccuinulated inthe still 71I may be recirculated through a pump 72 Vand pipel73 to the up- 'takelstills..v69, and the jpitch produced-therein can be returned through aV pipe 74 to the still 71. Similarly, the pitch may be recirculated through a pump 7 fan'd pipe 76 for further distillation in the 'still'711 The pitch pro duced inthestill 71 maybe withdrawn as desired through apipe 77and accumulated inatank78; y.. ,p

The gases? pass frombthe still 71 throu h a pipe 79 to an electrical precipitator '80 w ich maybe identical with the recipitator 49 as hereinbefore described. he pitch which separates from the gas inthe precipitator -may be withdrawn through a pipe 81 and delivered to atank 82 o r it may be` returned to the still 71. 'Ifhe clean gases pass through a pipe'83 to condensers or fractionators 84 arranged in series to condense desired oil constituents vfrom the gases. These oils may bedelivered through' pipes 85 to tanks 86. The gases are then delivered through an exhauster 87 and pipe 88 to the exhauster 27 where the lgases are mingled withgases from the remaining ovens of'the'battery.

,Referring to Fig. 6 of th'e drawings, three tank stills 90, 91 and 92 are' each connected by goose-necks 93 to groupsor` uptake stills 94, 95 and 96 which receive thehot coke-oven gases directly Jfrom the ovens. The tar tuV be distilled may be introduced to the tank? still 90 through a pipe 97 and suitable spray :nozzles in the still so that the tar is intimately 101 and `is delivered by a pipe 192 to the up vles take stills 95 and is subjected'to further distillation therein 'by intimate contactv with the hot coke-oven gases. 'It isl withdrawn through a pipe 103 and is delivered tothe tank still 92 for furtherdistillation with hot gases from the uptake stills 96. The pitch passes through a pump 104 and pipe 105 to the uptake stills 96, being subjected therein to final distillation with the hot coke-oven ases. It is withdrawn through a pipe 106. itch products may be withdrawn also .through pi es 107, 108, 109,110 andA 111. It will be un erstood that in each still intimate' contact between the hot cokefoven gases and the tar or pitch to be distilled is accomplished either by spraying the tar or pitch into the hot gases or by suitable agitation in the still to disseminate the tar or pitch iii-finely divided form throu h the ases. Thehot ases om t e tank still 92 ma be delivere through a pipe112 to the t still 91 for 'utilization therein in distilling tar or pitch and similarly` the gases from the tank still 91 may be elivered 'through a pipe 113 tothe tank still 90. The gases may, however, if desired, be withdrawn fromeach of the tanky stills for treatment in electrical that theseve'ral examples are illustrative and that various changes may be made in the,... form and'arrangement of the a paratus eme-v ployed and in the steps utilize without departing from the invention or sacrificing any "I still and means for bringing the residue into direct contact with the gases therein in the form of a spray.

y. In testimony whereof I alix my si precipitators 114, 115 and 116, for the pur- ,f-

poseof separating tarry and ,'solid congases maybe cooled then in suitable condensers 117,

stituents from the gases. I The clean 118 and 119 for lthe purpose of recovering the oondensable constituents.

If the gases conducted in succession through the several tank stills a single electrical precipitator 114 willserve for the cleaning of the gases which may be conveyed then through the condenser.l f

117. If the ases from the several tank stills are separate treated the condensate can be withdrawn t rough pipes 120, 121 and 122, and the gases may he conducted through the condensers in series throughpipes 123 and" 124. It will be understood that .suitable fjsj valves are rovided in the several pipe lines to ermit t -e direction of the tar and pitch an of the gases through the apparatus andthe withdrawal of diiferent products at several points therefrom, and that these valves will' he manipulated to permit the treatment of the tar or pitch in accordance with the roducts whichA are to be recovered. By modiigy gases afterseparation of the oils therefrom in the condenser may be subjected in the usual manner` to further treatment for the recovery of ammonia, light oils, etc., there- Severalembodiments of the invention involving the principles `set forth have `been` described in more or lessdetail in order that the application ofthese principles may be clearly understood. It will be understood ing. the operation as hereinbefore suggested, pitches having dierent melting pomtsand other characteristics can be with- L drawn and clean oilscan be recovered. The

y ature. STUART PARMELEE MIL ER.

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